The optimal approach for the ablation of persistent atrial fibrillation is undefined. Left atrial posterior wall isolation (LAPWI) is a promising lesion set, based on techniques for surgical AF ablation. The left atrial posterior wall can be isolated via catheter, surgical or hybrid ablation techniques. This MD thesis aims to inform a comparative trial of catheter versus hybrid ablation. In series of catheter and hybrid ablation with left atrial posterior wall isolation in patients with atrial fibrillation outcomes are suggested to be superior to published outcomes of alternative lesion sets. A complete lesion set with intact LAPWI ablation lines is important for outcomes and one advantage of a two-stage hybrid ablation may be that is provides greater chance of electrical isolation. It also gives rises to significant reductions in surface ECG P wave duration and dispersion which are associated with better ablation outcomes, possibly due to autonomic modulation. The benefits of hybrid ablation come at a cost of complications, however. Newer catheter ablation technologies such as electroporation may reduce risks and experiments on porcine models described in this thesis demonstrate how this is possible and provide a future avenue for research and development. A technique is also described for checking the LAPWI lesion set via the use of an oesophageal pacing electrode. Feasibility is demonstrated when compared to simultaneous intracardiac study and a standalone “outpatient” technique is developed. This technique could be used for research or as part of standard follow-up of LAPWI via catheter or surgery.

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